Between classes, when throngs of students stream into and out of Columbia University ’s campus, the security lines can back up like a TSA checkpoint. There’s a switch-back path of metal fencing that leads into a white tent, where two sets of guards check and then swipe campus ID cards before letting students in and out.

Columbia University agreed to implement a host of policy changes, including overhauling its rules for protests and conducting an immediate review of its Middle Eastern studies department.